In the prior art, planer mills have been orienting the lumber fed into the planer to place the most wane face and/or edge to the planer cutter which removes the largest amount of material thus providing the least wane on the finished planed lumber. Planer feeder automation systems have been in use for years. Typically, planer feeder automation includes piece orientation as described in a Forintek document #680-3366 dated August 2001. The lug loader such as described in U.S. Pat. No. 4,869,360 singulates the pieces and loads them onto a transfer for processing through a transverse scanner. The scanner and associated processor makes a decision and the piece is then processed to “Flip” the piece as necessary using a board flipper.
The main problem with the conventional manual planer infeed is that the operator would have to flip 100% of the pieces to properly view all faces, and some portion of those twice if the worse face is not correct after the first flip. Another problem with the conventional planer feeder is that when pieces press against each other, it makes flipping harder due to friction. With planers running at ever-faster speeds, the planer infeed operator may be taxed beyond his ability to consistently flip pieces to remove the most wane/defect from the worst face. Some of the pieces will require flipping and turning to orient the wane to the greatest depth-of-cut cutting tools.
Other systems have incorporated measurement and optimization of the piece in the sawmill, marking the piece, and then manually flipping the piece in the planer mill based on the faces marked. A further problem with the sawmill marking system is that the drying process may introduce other grade limiting characteristics which would change the decision. An improperly oriented piece has potential for either grade or volume depreciation.
Another prior art system of which applicant is aware employs a scanner in the planer mill to measure the wane and then sets the planer guides and cutters to place the heaviest cut at the most wane surfaces. This requires that the planer setworks make the adjustment rapidly between pieces or during the leading end processing where the variant material must later be trimmed. After drying, typical rough lumber has some excess length which will be trimmed after planing. This excess length could be as little as 1/16 inch or much higher if end trimming is required to remove poor grade material. A planer running at 2000 ft/min and processing ribbon feed material (ends butted) would need to rapidly set between pieces to achieve the same result as the described invention. For example, if setting is allowed to spoil ⅛ inch of length to be later trimmed off, the setting must occur in: 2000 ft=2000 (12) inches/sec=400 inches/sec.
min 60
⅛ inch of length, or 0.125″=0.0003125 seconds at 400 inches/sec which is a challenge and may not be feasible. If the mill allows an extra one inch in length then the sets must be achieved within 0.0025 seconds, which is still a challenge. The process could include a suitable gap between pieces to allow for the machine setting time and suffer the lost throughput as well as excessive machine beating as the planer rolls bounce from wood to no wood to wood again.
In the example of a nominal so-called ‘2×4’ or 2×4 board illustrated in FIG. 1a, the board thickness before going into the planer may be 1.650 inches (faces C, D) and the board width before going into the planer may be 3.700 inches (faces A, B). To achieve finished dimensions of 1.5 inches thickness, 3.7 inches width, the following amounts of excess wood may be removed by the planer:
                              a          )                                      1.650          ″                                      thickness                                                                                                -            0.032                    _                                      fixed  thickness removed  from  face  B                                                                                     =                      1.618            ″                                                                                        ⁢                                        b            )                                                1.618            ″                                                                                                                                                                          -                              0.118                ″                                      _                                                Excess  thickness  removed  from  face  A                                                                                                            =                          1.500              ″                                                            Finished  thickness  Dimension                                                            c          )                                      3.700          ″                                      width                                                                                                -                          0.032              ″                                _                                      Fixed  width  removed  from  edge  D                                                                                    =                      3.668            ″                                                                                                  d          )                                      3.668          ″                                                                                                                                      -            0168                    _                                      Excess width  removed  from  edge  C                                                                                    =                      3.500            ″                                                Finished  width  Dimension                    